because all the cool kids are doing it? Actually, I think it's smart to keep the constraint.

it's smart like a Twitterfox!

I agree, why the 140? Why not truncate it anyway if you have to send it to sms?

it'll ensure that desktop/phone clients and services can multi-post toTwitter/Plurk/Pownce. Not saying that's it, but it's a benefit

they are being forward-thinking and anticipating adding SMS later on